I am from WA too, I was diagnosed by Biopsy 19 months ago at Murdoch, both kids had blood test and DD also tested positive and went for a biopsy we went privately thru Murdoch although the gastroenterologist does not work privately anymore so you have to go thru PMH.
DS tested negative although I had him retested a year later when me and my daughter had our one year blood test and luckily I did as it came back positive.
I was told about an 18 month waiting list for the pead gastro at PMH. I was not happy about that and he had terrible pains and poos for a week so I took him to PMH ER, long horrible day but we did finally get to see a Gastro registrar and he agreed with the biopsy and since we went to the ER and had already seen a Gastro Registrar we didn't need to do the appointment with the pead Gastro and was put straight on the list for biopsy had to wait about 3-4 months we go in next week. Although thankfully my son is doing ok eating gluten, we just have him complain about tummy aches now and then, really we wouldn't have suspected CD if it wasn't for me and DD.
Reintroducing gluten is much harder
especially if he is getting so sick.
I would go to the PMH ER for sure
I think that is the first step, and if he was unwell at the time it would be even better for you although it would not be nice to purposely make him stick
I would also be ringing them often since they canceled your appt they should contact you need another one.
As for yourself, I would definitely do the biopsy, not only to confirm but for peace of mind I had the Endoscopy and Colonoscopy at the same time just to make sure there were no other nasties that come along with untreated CD. If you have private health its pretty quick, I only had to wait 2 week for the biopsy and 1 week for the results. I had Dr Chong and Murdoch.
The other reason I would do biopsy is one day there will be a vaccine and those who were not diagnosed correctly may not be entitled to it. I know that may be years down the track but your son may want to go down that road one day.
Sorry that was a bit long, Good luck x